CN116139872A - Catalyst for preparing HCN (hydrogen cyanide) by methanol ammoxidation and preparation method thereof - Google Patents
Catalyst for preparing HCN (hydrogen cyanide) by methanol ammoxidation and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a catalyst for preparing HCN by methanol ammoxidation and a preparation method thereof, wherein the catalyst comprises the following components: fe (Fe) 2 O 3 3.0‑7.0wt％，MoO 3 2.0‑6.0wt％，SiO 2 50‑80wt％，TiO 2 15-40wt%. The catalyst has high dispersity of active components and good mass transfer performance, and has excellent activity and selectivity when being used for preparing HCN by methanol ammoxidation.
Description
Technical Field
The invention relates to a catalyst for preparing HCN by methanol ammoxidation and a preparation method thereof, belonging to the technical field of catalysis.
Background
Hydrocyanic acid (HCN) is an important chemical intermediate with active properties, has wide application in the fields of medicines, pesticides, dyes, assistants, metallurgy and the like, and can be used for producing acetone cyanohydrin, adiponitrile, sodium cyanide, methionine, glycine, glyphosate, chelating agents and the like.
The industrial HCN production method mainly comprises an acrylonitrile byproduct method, a methane ammoxidation method (Anshi method), a light oil cracking method, a methanol ammoxidation method and the like.
The acrylonitrile byproduct method takes propylene, air and ammonia as raw materials, and the byproduct HCN is produced when the acrylonitrile is synthesized by catalytic ammoxidation, the technology is required to be close to acrylonitrile manufacturers, the HCN yield is only about 6 percent, and the application is limited.
The methane ammoxidation method uses methane, ammonia and air as raw materials, pt-Rh as catalyst, and the HCN is obtained by reaction at above 1000 ℃, and the HCN yield is only about 60-70%. The technical safety risk is high because of the wide explosion limit range of raw material methane, high reaction temperature, large reaction heat release and low ammonia gas utilization rate (only 60-70%).
The light oil cracking process is to react light oil, liquid ammonia, petroleum coke and nitrogen as material at 1450 deg.c to obtain HCN. As the raw materials, intermediate products and products are mostly flammable and explosive or highly toxic compounds, the production process has high risk and high accident potential, and the route is not popularized and applied.
The methanol ammoxidation method is to prepare HCN by taking methanol, ammonia and air as raw materials, and has the advantages of low reaction temperature, low energy consumption, safer process and the like. The catalyst is the core of the technology, methanol ammoxidation catalysts are reported in a plurality of patents, the main catalytic system is Fe-Mo oxide, P-V oxide, mn-P oxide, pt-Rh catalyst and the like, and the active phase of most reported catalysts contains Fe and Mo.
U.S. patent publication No. 3,182 discloses an Fe-Mo catalyst a Mo b O c The patent adds a molybdenum salt solution to an iron salt solution to form a precipitate, and then adds a silica sol, which is expected to be detrimental to the dispersion of molybdenum and iron, with a hydrocyanic acid yield of about 86.4%. In patent US3911089 Mo is disclosed as an ammoxidation catalyst a Bi b Fe c X d Y e Z f O g X is one of Cr, mn, co, ni, zn, cd, sn, W and Pb, Y is one or more of transition elements, the catalyst composition is complex, and the HCN yield is 86%. Patent EP0322796 discloses a catalyst Mo which is commonly used in ammoxidation of one or more organic compounds of methanol, propylene and isobutylene e D f E g F h O y D is mainly selected from Mn, fe, ni, bi, zn, and the HCN yield is only 81%. None of the above patents mention the manner in which the catalyst is shaped and the reactivity of the shaped catalyst of full particle size.
Chinese patent publication CN1112243 proposes Mo a Bi b Me c Te d Q e R f X g Y h O z A catalyst comprising Mo/Bi and at least one element selected from the group consisting of iron and cerium. The catalyst proposed in patent US4461752 is Fe a Cu b Sb c Mo d Me e Te f Q g O h (SiO 2 ) i . The methanol ammoxidation catalyst disclosed in patent US5158787 is Fe a Cu b Sb c V d Mo e W f P g Q h R i S j O k (SiO 2 ) l . The raw materials required for preparing the catalyst are numerous, the preparation process is complex, and the HCN yield is obviously reduced when the preparation composition slightly deviates from an empirical formula.
Chinese laid-open patent CN106669705a discloses a catalyst for methanol ammoxidation and a method for preparing the same, wherein a binder is added during extrusion molding, which is disadvantageous for catalyst diffusion. The patent does not examine the performance of the catalyst formed by whole particle size, and the catalyst formed by conventional extrusion has different lengths, so that the catalyst is not suitable for being used in a tubular reactor (high requirement on filling uniformity).
In addition, the catalyst containing Fe and Mo has the capability of oxidizing methanol to generate formaldehyde, the generated formaldehyde can further react with HCN to generate hydroxyacetonitrile and the like, and the formaldehyde, the hydroxyacetonitrile and other byproducts have very active properties, are easy to polymerize and easily cause the blockage of a subsequent separation system. None of the above patents mention the effect of catalyst composition and preparation process on formaldehyde and hydroxyacetonitrile formation.
At present, the methanol ammoxidation catalyst prepared by the prior art has the problems of complex catalyst composition, high preparation cost, poor preparation repeatability and the like. Therefore, the development of the methanol ammoxidation catalyst with excellent reaction performance, simple preparation process and low cost has great significance.
Disclosure of Invention
The invention aims to provide a catalyst for preparing HCN by methanol ammoxidation and a preparation method thereof, and the catalyst prepared by the method has low cost and excellent activity and selectivity.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a catalyst for preparing HCN by methanol ammoxidation, which comprises the following components in percentage by weight based on 100% of the total mass of the catalyst:
in the catalyst, fe and Mo are active components of the catalyst; siO (SiO) 2 And TiO 2 Is a catalyst carrier, siO 2 And TiO 2 The compound catalyst carrier is favorable for regulating and controlling the interaction force between the carrier and the active component so as to obtain the catalyst with high activity.
The invention also provides a preparation method of the methanol ammoxidation catalyst, which comprises the following steps of:
(a) Adding water into a reaction kettle, then adding a molybdenum-containing compound, and fully stirring until the molybdenum-containing compound is dissolved; adding an iron-containing compound, and fully stirring until the iron-containing compound is dissolved to obtain a mixed solution;
(b) Mixing silica sol, titanium sol, quartz powder and pore-forming agent, and fully stirring to obtain suspension;
(c) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying and roasting at a low temperature;
(d) Sieving the dried solid (for example, a 20-mesh sieve), adding an inorganic pore-forming agent and a release agent, tabletting, forming and roasting to obtain the methanol ammonia oxidation catalyst.
In the method of the present invention, the molybdenum-containing compound of step (a) is selected from one or more of ammonium dimolybdate, ammonium tetramolybdate and ammonium heptamolybdate; and/or: the iron-containing compound is selected from one or more of ferric nitrate, ferric chloride and ferric acetate.
In the method of the invention, the mass concentration of the iron-containing compound and the molybdenum-containing compound in the mixed solution in the step (a) is 30-50wt%. When the mass concentration of the molybdenum-containing compound and the iron-containing compound is too low, a large amount of water is required to be evaporated in the drying process, so that energy waste is caused; when the mass concentrations of the iron-containing compound and the molybdenum-containing compound are too high, on the one hand, sufficient dissolution is difficult, and on the other hand, the dispersion of the active components Fe and Mo is also affected.
In the method of the invention, the particle size of the quartz powder in the step (b) is 80-150 meshes, and SiO in the catalyst product is 2 The fraction from the quartz powder is 20-40%. The quartz powder with larger particle size is beneficial to the mass transfer performance of the catalyst and is not beneficial to the strength of the catalyst; the quartz powder with smaller particle size is beneficial to the strength of the catalyst and is unfavorable for improving the mass transfer performance of the catalyst. The quartz powder with moderate particle size can improve the mass transfer performance of the catalyst and reduce the occurrence of side reactions on the premise of ensuring the strength of the catalyst.
In the method of the invention, the organic pore-forming agent in the step (b) is PP or PE powder, and the particle size of the powder is more than 150 meshes. When the particle size of the pore-forming agent is too thick, the pore-forming agent is difficult to disperse uniformly, and the pore-forming effect is poor; when the particle size of the pore-forming agent is too small, the formed pore canal is smaller, and the effect of improving the mass transfer performance of the catalyst is limited. The mass ratio of the pore-forming agent to the quartz powder is 1:5-20.
In the method of the invention, the silica sol in the step (b) is acidic silica sol, the concentration is 20-40wt% and the particle size is 20-40nm; the titanium sol is acidic titanium sol, the concentration is 10-20wt% and the particle size is 20-40nm. The particle size of the sol is larger when the concentration of the silica sol and the titanium sol is too high, which is not beneficial to the dispersion of active components, and the catalyst preparation efficiency is lower and the energy consumption is higher when the concentration of the silica sol and the titanium sol is too low.
In the method of the invention, the drying temperature in the step (c) is 90-120 ℃, preferably 100-120 ℃ and the drying time is 4-12 hours; the low-temperature roasting temperature is 250-400 ℃ and the roasting time is 2-8h. The drying temperature is 90-120deg.C (e.g. 100deg.C, 110deg.C), and the drying time is 4-12h (e.g. 5h, 8h, 10 h); the low temperature roasting temperature is 250-400 ℃ (e.g. 250 ℃, 300 ℃, 350 ℃) and the roasting time is 2-8h (e.g. 3h, 5h, 7 h).
In the method of the invention, the inorganic pore-forming agent in the step (d) is one or more of ammonium carbonate, ammonium bicarbonate and ammonium nitrate; the addition amount of the inorganic pore-forming agent is 3-10wt% of the mass of the solid after sieving. When the addition amount of the inorganic pore-forming agent is small, the pore-forming effect cannot be achieved, and when the addition amount of the inorganic pore-forming agent is large, the strength of the catalyst is adversely affected.
In the method of the invention, the release agent in the step (d) is graphite, and the addition amount is 0.5-2.0% (for example, 0.5%, 1.0% and 1.5%) of the mass of the sieved powder.
In the method of the present invention, the baking temperature in the step (d) is 450-650 ℃ (e.g. 450 ℃, 500 ℃, 550 ℃) and the baking time is 2-8 hours (e.g. 3 hours, 5 hours, 7 hours).
In the method of the invention, the catalyst molded product in the step (d) is hollow ring-shaped with regular granularity, the outer diameter is 4-6mm, the inner diameter is 1-3mm, and the length is 4-8mm.
The catalyst is used for preparing hydrocyanic acid by ammoxidation of methanol under the process conditions:
the catalyst evaluation is carried out by adopting a small-scale molten salt device, the inner diameter of a reaction tube is 25-40mm, the loading amount of the catalyst with the whole granularity is 30-100ml, and the set temperature of molten salt is 350-390 ℃; raw material ammonia, methanol and airThe gas mole ratio is 1:0.8 to 1.2: 80-120; normal pressure reaction with space velocity of 2000-5000h -1 。
The invention has the beneficial effects that:
in the preparation method of the catalyst, firstly, the iron-molybdenum mixed solution is prepared, then, the quartz powder and the organic pore-forming agent are added into the carrier solution, and finally, the inorganic pore-forming agent is added, so that the catalyst for alcohol ammoxidation has the advantages of high dispersity of active components and smooth pore channels of the catalyst, and has excellent activity and HCN selectivity when being used for preparing HCN by methanol ammoxidation, and the preparation cost is low, and byproducts formaldehyde and hydroxyacetonitrile are few.
Detailed Description
So that the technical features and content of the present invention can be understood in detail, preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention have been described in the examples, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein.
< source of raw materials >
Methanol, available from Shanghai Ala Biochemical technologies Co., ltd;
ferric nitrate, purchased from Shanghai Ala Biochemical technologies Co., ltd;
ammonium molybdate, available from Shanghai Ala Biochemical technologies Co., ltd;
quartz powder, purchased from beijing enokio technology limited, with particle size > 200 mesh;
silica sol available from Corhn silicon products, inc. in Linyi, inc.;
titanium sol, available from Xuancheng Jinrui New Material Co., ltd;
ammonium carbonate, available from Shanghai Ala Biochemical technologies Co., ltd;
graphite, available from Shanghai Ala Biochemical technologies Co., ltd.
< test method >
The methanol conversion rate and the hydroxyacetonitrile selectivity are calculated after analysis by using an Agilent 7820A gas chromatograph, and the test conditions comprise: using DB-5 chromatographic column and FID detector to obtain vaporThe temperature of the chemical chamber is 260 ℃, the temperature of the detector is 260 ℃, and the carrier gas is high-purity N 2 The flow rate was 30ml/min.
The HCN generated by the reaction in a certain time is absorbed by sodium hydroxide solution, and the HCN selectivity is measured and calculated by adopting a silver nitrate titration method.
Example 1
(1) 102.3g of water is firstly added into the reaction kettle, then 9.6g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 45.5g of ferric nitrate (ferric nitrate nonahydrate) is added, and the mixture is fully stirred until the mixture is completely dissolved, so as to obtain a mixed solution.
(2) 280.0g of silica sol (concentration: 30wt%, particle size: 20-30 nm), 316.0g of titanium sol (concentration: 20wt%, particle size: 20-30 nm), 36.0g of quartz powder and 3.6g of PP powder (> 200 mesh) were mixed and sufficiently stirred to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 100 ℃ for 6 hours and roasting at 250 ℃ for 4 hours.
(4) Sieving the dried solid with a 20-mesh sieve, adding 2.0g of graphite and 10g of ammonium carbonate, tabletting, and roasting at 500 ℃ for 4 hours to obtain a methanol ammonia oxidation catalyst A, wherein the outer diameter of catalyst particles is 4mm, the inner diameter is 1.5mm, and the length is 4mm;
catalyst performance evaluation:
the catalyst evaluation is carried out by adopting a small-scale molten salt device, the inner diameter of a reaction tube is 27mm, the loading amount of the catalyst with the whole granularity is 50ml, and the temperature of molten salt is set to 390 ℃; the molar ratio of raw material ammonia, methanol and air is 4:4.4:91.6; atmospheric pressure reaction with a space velocity of 3000h -1 . Sampling and analyzing after the reaction feed is stabilized for 1-2 hours, and the ammoxidation result is shown in table 1.
Example 2
(1) 94.3g of water is firstly added into the reaction kettle, then 11.0g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 35.4g of ferric nitrate is added, and the mixture is fully stirred until the mixture is completely dissolved, thus obtaining a mixed solution.
(2) 289.3g of silica sol (concentration: 30wt%, particle size: 30-40 nm), 293.3g of titanium sol (concentration: 15wt%, particle size: 30-40 nm), 86.8g of quartz powder and 4.3g of PE powder (> 300 mesh) were mixed and stirred sufficiently to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 100 ℃ for 12 hours and roasting at 300 ℃ for 4 hours; .
(4) Sieving the dried solid with a 20-mesh sieve, adding 2.0g of graphite and 6g of ammonium carbonate, tabletting, and roasting at 550 ℃ for 6 hours to obtain a methanol ammonia oxidation catalyst B, wherein the outer diameter of catalyst particles is 3.5mm, the inner diameter is 1.0mm, and the length is 3.5mm;
the ammoxidation of catalyst B was carried out under the process conditions and the operation described in example 1.
Example 3
(1) 166.6g of water is added into the reaction kettle, then 7.4g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 55.7g of ferric nitrate is added, and the mixture is fully stirred until the mixture is completely dissolved, thus obtaining a mixed solution.
(2) 211.3g of silica sol (concentration: 40wt%, particle diameter: 20-30 nm), 353.3g of titanium sol (concentration: 15wt%, particle diameter: 20-30 nm), 84.5g of quartz powder and 5.6g of PP powder (> 400 mesh) were mixed and sufficiently stirred to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 110 ℃ for 6 hours and roasting at 350 ℃ for 4 hours; .
(4) And (3) sieving the dried solid through a 20-mesh sieve, adding 2.0g of graphite and 14g of ammonium carbonate, tabletting, forming, and roasting at 450 ℃ for 8 hours to obtain the methanol ammonia oxidation catalyst C, wherein the outer diameter of catalyst particles is 4.5mm, the inner diameter is 2.0mm, and the length is 4.5mm.
The ammoxidation of catalyst C was carried out under the process conditions and the operation described in example 1.
Example 4
(1) 110.3g of water is firstly added into the reaction kettle, then 6.9g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 60.7g of ferric nitrate is added, and the mixture is fully stirred until the mixture is completely dissolved, thus obtaining a mixed solution.
(2) 375.0g of silica sol (concentration: 30wt%, particle size: 30-40 nm), 162.0g of titanium sol (concentration: 20wt%, particle size: 30-40 nm), 112.5g of quartz powder and 14.1g of PE powder (> 500 mesh) were mixed and sufficiently stirred to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 110 ℃ for 4 hours and roasting at 400 ℃ for 4 hours; .
(4) And (3) sieving the dried solid through a 20-mesh sieve, adding 2.0g of graphite and 18g of ammonium carbonate, tabletting, forming, and roasting at 600 ℃ for 3 hours to obtain the methanol ammonia oxidation catalyst D, wherein the outer diameter of the catalyst particles is 5mm, the inner diameter is 2mm, and the length is 5mm.
Catalyst D was subjected to ammoxidation under the process conditions and operating procedures described in example 1.
Example 5
(1) 67.8g of water is firstly added into the reaction kettle, then 8.6g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 40.5g of ferric nitrate is added, and the mixture is fully stirred until the mixture is completely dissolved, thus obtaining a mixed solution.
(2) 280.0g of silica sol (concentration 40wt%, particle size 20-30 nm), 300g of titanium sol (concentration 15wt%, particle size 20-30 nm), 112.0g of quartz powder and 16.8g of PP powder (> 200 mesh) were mixed and sufficiently stirred to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 110 ℃ for 8 hours and roasting at 300 ℃ for 4 hours; .
(4) And (3) sieving the dried solid through a 20-mesh sieve, adding 2.0g of graphite and 10g of ammonium carbonate, tabletting, forming, and roasting at 550 ℃ for 4 hours to obtain the methanol ammonia oxidation catalyst E, wherein the outer diameter of the catalyst particles is 4mm, the inner diameter is 2mm, and the length is 4mm.
The ammoxidation of catalyst E was carried out under the process conditions and the operation described in example 1.
Example 6
(1) 85.7g of water is firstly added into the reaction kettle, then 7.8g of ammonium heptamolybdate is added, and the mixture is fully stirred until the mixture is dissolved; then 42.5g of ferric nitrate is added, and the mixture is fully stirred until the mixture is completely dissolved, thus obtaining a mixed solution.
(2) 270.0g of silica sol (concentration 40wt%, particle size 30-40 nm), 176g of titanium sol (concentration 20wt%, particle size 30-40 nm), 108.0g of quartz powder and 9.0g of PE powder (> 500 mesh) were mixed and stirred sufficiently to obtain a suspension.
(3) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 120 ℃ for 6 hours and roasting at 350 ℃ for 4 hours.
(4) And (3) sieving the dried solid through a 20-mesh sieve, adding 2.0g of graphite and 6g of ammonium carbonate, tabletting, forming, and roasting at 500 ℃ for 4 hours to obtain the methanol ammonia oxidation catalyst F, wherein the outer diameter of the catalyst particles is 4.5mm, the inner diameter is 1.5mm, and the length is 4.5mm.
The ammoxidation of catalyst F was carried out under the process conditions and the operation described in example 1.
Comparative example 1
The procedure for preparing a methanol ammoxidation catalyst was the same as in example 1, except that no titanium sol was added in step (2), to prepare catalyst G.
The ammoxidation of catalyst G was carried out under the process conditions and the operation described in example 1.
Comparative example 2
The procedure for preparing the methanol ammoxidation catalyst was the same as in example 1, except that in step (2), no quartz powder was added to prepare catalyst H.
Catalyst H was subjected to ammoxidation under the process conditions and operating procedures described in example 1.
Comparative example 3
The procedure for preparing the methanol ammoxidation catalyst was the same as in example 1, except that PP powder (> 400 mesh) was not added in step (2) to prepare catalyst I.
The ammoxidation of catalyst I was carried out under the process conditions and the operation described in example 1.
Comparative example 4
(1) 63.9g of water and 45.5g of ferric nitrate are added into the reaction kettle, the mixture is fully stirred until the mixture is dissolved, 48g of ammonium heptamolybdate aqueous solution with the concentration of 20 weight percent is added, and then ammonia water is added to adjust the pH value of the system to 2.0, so as to obtain slurry containing molybdenum and iron compounds.
(2) 280.0g of silica sol (concentration: 30wt%, particle diameter: 20-30 nm), 316.0g of titanium sol (concentration: 20wt%, particle diameter: 20-30 nm), 36.0g of quartz powder and 3.6g of pore-forming agent PP powder (> 200 mesh) were mixed and sufficiently stirred to obtain a suspension.
(3) Adding the slurry obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying at 100 ℃ for 6 hours and roasting at 250 ℃ for 4 hours.
The catalyst K ammoxidation is carried out under the process conditions and operating procedures described in example 1.
Table 1 results of catalyst evaluation
| Methanol conversion% | HCN Selectivity% | Formaldehyde selectivity% | Hydroxyacetonitrile selectivity% | |
| Catalyst A | 99.0 | 89.3 | 0.033 | 0.22 |
| Catalyst B | 98.9 | 89.5 | 0.026 | 0.19 |
| Catalyst C | 99.2 | 89.4 | 0.0089 | 0.15 |
| Catalyst D | 98.7 | 89.5 | 0.012 | 0.17 |
| Catalyst E | 98.9 | 89.2 | 0.022 | 0.18 |
| Catalyst F | 99.1 | 89.5 | 0.017 | 0.20 |
| Catalyst G | 98.2 | 89.6 | 0.3 | 1.06 |
| Catalyst H | 96.9 | 87.0 | 0.15 | 0.82 |
| Catalyst I | 97.3 | 88.5 | 0.12 | 0.76 |
| Catalyst K | 95.9 | 87.3 | 0.37 | 1.23 |
As can be seen from table 1, catalysts a to F have good activity and selectivity, whereas the catalysts described in comparative examples 1 to 4 either have low activity or poor selectivity. The results show that the methanol ammoxidation catalyst prepared by the invention has low preparation cost, high dispersity of active components and smooth catalyst pore channels, and has excellent activity and HCN selectivity when being used for preparing HCN by methanol ammoxidation, and few byproducts of formaldehyde and hydroxyacetonitrile.
By comparing example 1 with comparative example 1, it is demonstrated that the incorporation of Ti in the catalyst is advantageous for improving the catalyst activity and reducing the amount of formaldehyde produced.
By comparing example 1 with comparative example 2, it is demonstrated that the introduction of quartz powder of suitable particle size improves the catalyst diffusion performance and increases the methanol conversion.
By comparing example 1 with comparative example 3, it is demonstrated that the introduction of pore formers during the preparation process is advantageous for improving the mass transfer properties of the catalyst and increasing the methanol conversion.
Comparison of comparative example 4 and example 1 shows that the catalyst prepared by the method of comparative example 4 (slurry containing molybdenum and iron compound) has poor dispersion of the active component, and is disadvantageous in catalyst activity, and also causes an increase in formaldehyde and hydroxyacetonitrile as byproducts.
Claims (11)
1. A catalyst for preparing HCN by methanol ammoxidation, which is characterized by comprising the following components in percentage by weight based on 100% of the total mass of the catalyst:
2. a method for preparing the catalyst as claimed in claim 1, comprising the steps of, in proportion:
(a) Adding water into a reaction kettle, then adding a molybdenum-containing compound, and fully stirring until the molybdenum-containing compound is dissolved; adding an iron-containing compound, and fully stirring until the iron-containing compound is dissolved to obtain a mixed solution;
(b) Mixing silica sol, titanium sol, quartz powder and an organic pore-forming agent, and fully stirring to obtain a suspension;
(c) Adding the mixed solution obtained in the step (a) into the suspension obtained in the step (b), fully stirring, drying and roasting at a low temperature;
(d) Sieving the dried solid, adding an inorganic pore-forming agent and a release agent, tabletting, forming and roasting to obtain the methanol ammoxidation catalyst.
3. The method of claim 2, wherein the molybdenum-containing compound of step (a) is one or more of ammonium dimolybdate, ammonium tetramolybdate, and ammonium heptamolybdate; and/or:
the iron-containing compound is selected from one or more of ferric nitrate, ferric chloride and ferric acetate.
4. A method according to claim 2 or 3, wherein the mass concentration of the iron-containing compound and the molybdenum-containing compound in the mixed solution in step (a) is 30 to 50wt%.
5. The method of any one of claims 2 to 4, wherein the quartz powder in step (b) has a particle size of 80 to 150 mesh, and the SiO in the catalyst product is 2 The fraction from the quartz powder is 20-40wt%.
6. The method according to any one of claims 2 to 5, wherein the organic pore-forming agent in step (b) is PP or PE powder with a particle size of > 150 mesh and the mass ratio of pore-forming agent to quartz powder is 1:5-20.
7. The method according to any one of claims 2 to 6, wherein the silica sol in step (b) is an acidic silica sol having a concentration of 10 to 20wt% and a particle size of 20 to 40nm; the titanium sol is acidic titanium sol, the concentration is 20-30wt% and the particle size is 20-40nm.
8. The method according to any one of claims 2 to 7, wherein the drying temperature in step (c) is 100 to 120 ℃ and the drying time is 4 to 12 hours; the low-temperature roasting temperature is 250-400 ℃ and the roasting time is 2-8h.
9. The method of any one of claims 2-8, wherein the inorganic pore-forming agent of step (d) is one or more of ammonium carbonate, ammonium bicarbonate, and ammonium nitrate; the addition amount of the inorganic pore-forming agent is 3-10wt% of the mass of the solid after sieving.
10. The method of any one of claims 2 to 9, wherein the firing temperature in step (d) is 450 to 650 ℃ and the firing time is 2 to 8 hours.
11. The method of any one of claims 2-10, wherein the catalyst shaped article of step (d) is a regular particle size hollow ring having an outer diameter of 3-5mm, an inner diameter of 1-3mm, and a length of 4-8mm.
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| CN202111381675.1A CN116139872A (en) | 2021-11-22 | 2021-11-22 | Catalyst for preparing HCN (hydrogen cyanide) by methanol ammoxidation and preparation method thereof |
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| CN202111381675.1A CN116139872A (en) | 2021-11-22 | 2021-11-22 | Catalyst for preparing HCN (hydrogen cyanide) by methanol ammoxidation and preparation method thereof |
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